I. Field of the Invention
This invention is directed to a flashing feed inlet used in a separation tower and to a method of introducing a substantially liquid feed stream into the separation tower which, after flashing, reduces the entrainment of the liquid portion of the feed in the vapor and the maldistribution of the vapor portion of the feed.
II. Description of the Prior Art
Vapor/liquid separation towers, such as distillation columns, are extensively used in chemical engineering industries. The towers efficiently and effectively separate the feedstock introduced thereinto into a number of desired fractions if the feedstock is introduced into the column at the conditions of temperature and pressure substantially equal to or lower than those prevailing within the column. However, if the temperature and/or pressure of the feedstock introduced into the column is higher than that prevailing within it, a steady-state upsetting condition known as "flashing" will occur in the column. Flashing vaporizes at least a portion of the feed and produces vapor at a very high velocity, e.g., 50 feet per second (ft/sec), which causes the entrainment of a substantial amount of the liquid portion of the feedstock in the vapor and maldistribution of the vapor. The entrainment of the liquid portion of the feedstock and/or maldistribution of the vapor portion of the feed decrease the efficiency of the separation tower.
Heretofore-known devices for promoting a uniform distribution of the feedstock in the tower did not address the problem of flashing of the feedstock. The emphasis has been placed instead on the efficient distribution of the liquid feedstock introduced into the column and the phenomenon of flashing of the portion of the liquid feedstock into vapor was either not recognized or not addressed by those skilled in the art.
Accordingly, it is a primary object of the present invention to provide a method and apparatus minimizing the adverse effects of flashing experienced upon the introduction of a liquid feed having higher temperature and/or pressure than those within the separation tower into which the feed is introduced.
Additional objects of the invention will become apparent to those skilled in the art from the following description thereof.